The present invention relates generally to integrated circuit devices. In particular, the present invention provides a magnetoresistive sensor system and related structure and methods of operation. Additionally, the applications include at least a sensor application or magnetoresistive applications, system applications, among others. But it will be recognized that the invention has a much broader range of applicability.
Research and development in integrated microelectronics have continued to produce astounding progress in CMOS, magnetic field sensors, and MEMS (MicroElectroMechanical systems). CMOS technology has become the predominant fabrication technology for integrated circuits (IC). In layman's terms, microelectronic ICs are the “brains” of an integrated device which provides decision-making capabilities, whereas MEMS, magnetic field sensors, and others, are the “eyes” and “arms” that provide the ability to sense and control the environment. Some examples of the widespread application of these technologies are the switches in radio frequency (RF) antenna systems, such as those in the iPhone™ device by Apple, Inc. of Cupertino, Calif., and the Blackberry™ phone by Research In Motion Limited of Waterloo, Ontario, Canada, and accelerometers in sensor-equipped game devices, such as those in the Wii™ controller manufactured by Nintendo Company Limited of Japan. Though they are not always easily identifiable, these technologies are becoming ever more prevalent in society every day.
Beyond consumer electronics, use of IC, magnetoresistive, and MEMS technology has limitless applications through modular measurement devices such as accelerometers, angular rate sensors, transducers, actuators, and other sensors and devices. In conventional vehicles, accelerometers and angular rate sensors are used to deploy airbags and trigger dynamic stability control functions, respectively. Magnetoresistive sensors are commonly used in compass systems, such as those used in aircrafts to determine heading, pitch and roll. MEMS gyroscopes can also be used for image stabilization systems in video and still cameras, and automatic steering systems in airplanes and torpedoes. Biological MEMS (Bio-MEMS) implement biosensors and chemical sensors for Lab-On-Chip applications, which integrate one or more laboratory functions on a single millimeter-sized chip only. Other applications include Internet and telephone networks, security and financial applications, health care and medical systems and the like. Magnetic sensors have also been used in applications requiring proximity switching, positioning, speed detection, current sensing and the like. As described previously, ICs, magnetic field sensors, and MEMS can be used to practically engage in various type of environmental interaction.
Although highly successful, ICs and in particular magnetoresistive sensors still have limitations. Similar to IC development, magnetoresistive sensor and MEMS development, which focuses on increasing performance, reducing size, and decreasing cost, continues to be challenging. Additionally, applications of magnetoresistive sensors and MEMS often require increasingly complex microsystems that desire greater computational power. These and other limitations of conventional magnetic sensors, MEMS, and ICs may be further described throughout the present specification and more particularly below.
From the above, it is seen that techniques for improving operation of integrated circuit devices, magnetoresistive sensors, and MEMS are highly desired.